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Papers by Shamsher Prakash

Journal of Geotechnical Engineering, Feb 1, 1996

... Shamsher Prakash Fellow, ASCE, Sanjeev Kumar. Abstract. ... An example problem is included to... more ... Shamsher Prakash Fellow, ASCE, Sanjeev Kumar. Abstract. ... An example problem is included to demonstrate its use. Based on this method, the computed load deflections have been compared with the observed ones and with those based on p-y analysis. ...

Journal of Geotechnical Engineering, 1989

The behavior of piles in seismic areas is significantly affected if the soil liquefies. The stren... more The behavior of piles in seismic areas is significantly affected if the soil liquefies. The strength of the soil and its stiffness decrease due to the increase in pore water pressure. The observed pile damage during earthquakes has provided an insight into the mechanism of soil-pile interaction in liquefying soils. The piles in liquefied soil may undergo large lateral displacements and my fail due to bending or buckling. The paper discusses the observed performance of piles in liquefying soils and the suggested methods for their design.

Journal of the Soil Mechanics and Foundations Division, 1971

This paper presents a comparison of observed computed response of a single pile. Full scale dynam... more This paper presents a comparison of observed computed response of a single pile. Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile driven 17m in a soil profile of uniform silty sand. Horizontal deflection of the pile at the mud line was measured by applying predetermined horizontal load increments during the static test. The dynamic load tests were conducted to determine the amplitude frequency response of the pile subjected to vertical and horizontal vibrations. The natural frequency of free vibrations in the horizontal direction was also measured. The soil properties were determined by conducting in-situ and laboratory tests. The response of the single piles was calculated and compared with the observed response.

The shallow foundations may be subjected to dynamic loads by machine operation or by seismic load... more The shallow foundations may be subjected to dynamic loads by machine operation or by seismic loading. A comparison of observed and predicted response is presented for the case of machine foundations based on observed data obtained by conducting vibration tests on two concrete blocks. For case of shallow foundations for seismic loaoding the recent developments in determining bearing capacity and settlements are discussed and the need for research for developing rational design procedures in this area is highlighted. 1INTRODUCTION The shallow foundations in the form rigid conctrete blocks are commonly used to support reciprocating type machine foundations. These foundations are also commonly used for supporting structural loads which may be static loads or a combination of static and seismic loads. When any foundation is used to support combination of staic as well dynamic loads , it must satisfy the stability criteria for both static as well dynamic loads.

Nature genetics, 2000

Oxidative damage to DNA has been proposed to have a role in cancer and ageing. Oxygen-free radica... more Oxidative damage to DNA has been proposed to have a role in cancer and ageing. Oxygen-free radicals formed during normal aerobic cellular metabolism attack bases in DNA, and 7, 8-dihydro-8-oxoguanine (8-oxoG) is one of the adducts formed. Eukaryotic replicative DNA polymerases replicate DNA containing 8-oxoG by inserting an adenine opposite the lesion; consequently, 8-oxoG is highly mutagenic and causes G:C to T:A transversions. Genetic studies in yeast have indicated a role for mismatch repair in minimizing the incidence of these mutations. In Saccharomyces cerevisiae, deletion of OGG1, encoding a DNA glycosylase that functions in the removal of 8-oxoG when paired with C, causes an increase in the rate of G:C to T:A transversions. The ogg1Delta msh2Delta double mutant displays a higher rate of CAN1S to can1r forward mutations than the ogg1Delta or msh2Delta single mutants, and this enhanced mutagenesis is primarily due to G:C to T:A transversions. The gene RAD30 of S. cerevisiae en...

Contemporary Topics in In Situ Testing, Analysis, and Reliability of Foundations, 2009

Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile t... more Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile that was driven 17m in a soil profile of uniform silty sand and the amplitude frequency response of the pile subjected to vertical and horizontal vibrations was observed. The natural frequency of free vibrations in the horizontal direction was also measured. The soil properties were determined by conducting in-situ and laboratory tests. A comparison of observed and predicted pile response is presented . A comparison of the computed and observed pile response based on the data reported in literature is also presented briefly.

Shallow foundations may experience a reduction in bearing capacity and increase in settlement and... more Shallow foundations may experience a reduction in bearing capacity and increase in settlement and tilt due to seismic loading. The reduction in bearing capacity depends on the nature and type of soil and ground acceleration parameters in non-liquefiable soils. In liquefying soils, the buildings on shallow footings may settle and tilt excessively. The soil- pile behavior under earthquake loading is generally non-linear, which is accounted for by defining soil- pile stiffness in terms of strain dependent soil modulus. Several behavioral and design aspects of shallow foundations and piles subjected to earthquakes have been critically reviewed, both in non-liquefiable and liquefiable soils.

Dynamic Response and Soil Properties, 2007

Geotechnical Earthquake Engineering and Soil Dynamics IV, 2008

Earth Retention Conference 3, 2010

Art of Foundation Engineering Practice, 2010

Design of foundations in earthquake prone areas needs special considerations. Shallow foundations... more Design of foundations in earthquake prone areas needs special considerations. Shallow foundations may experience a reduction in bearing capacity and increase in settlement and tilt due to seismic loading. The reduction in bearing capacity depends on the nature and type of soil and ground acceleration parameters. In the case of piles, the soil-pile behavior under earthquake loading is generally non-linear. The nonlinearity must be accounted for by defining soil-pile stiffness in terms of strain dependent soil modulus. A comparison of observed and predicted pile behavior under dynamic loads has attracted the attention of several investigators. The lateral dynamic pile response of single piles predicted by analytical models often yields higher natural frequencies and lower resonant amplitudes compared to those determined from field tests in horizontal vibrations only. This has been found to be due to overestimated shear modulus and radiation damping of the soil. The authors made an investigation to determine a simple method to improve the theoretical predictions of piles embedded in fine soils. Based upon this investigation shear strain dependent reduction factors are proposed for determining the shear modulus and damping for pile response calculations.

SOILS AND FOUNDATIONS, 1980

抄録 The paper discusses the geotechnical investigations planned and carried out for a cement facto... more 抄録 The paper discusses the geotechnical investigations planned and carried out for a cement factory in boulder deposit. A cement factory normally has very typical structures, eg heavily loaded structures as cement silo, tall structures as preheater tower. In addition to ...

The behavior of piles in seismic areas is significantly affected if the soil liquefies. The stren... more The behavior of piles in seismic areas is significantly affected if the soil liquefies. The strength of the soil and its stiffness decrease due to the increase in pore water pressure. The observed pile damage during earthquakes has provided an insight into the mechanism of soil-pile interaction in liquefying soils. The piles in liquefied soil may undergo large lateral displacements and my fail due to bending or buckling. The paper discusses the observed performance of piles in liquefying soils and the suggested methods for their design.

Molecular and Cellular Biology, 2001

Mutations in the human CSB gene cause Cockayne syndrome (CS). In addition to increased photosensi... more Mutations in the human CSB gene cause Cockayne syndrome (CS). In addition to increased photosensitivity, CS patients suffer from severe developmental abnormalities, including growth retardation and mental retardation. Whereas a deficiency in the preferential repair of UV lesions from the transcribed strand accounts for the increased photosensitivity of CS patients, the reason for developmental defects in these individuals has remained unclear. Here we provide in vivo evidence for a role of RAD26, the counterpart of the CSB gene in Saccharomyces cerevisiae, in transcription elongation by RNA polymerase II, and in addition we show that under conditions requiring rapid synthesis of new mRNAs, growth is considerably reduced in cells lacking RAD26. These findings implicate a role for CSB in transcription elongation, and they strongly suggest that impaired transcription elongation is the underlying cause of the developmental problems in CS patients.

Molecular and Cellular Biology, 2001

The yeast RAD30-encoded DNA polymerase (Pol) bypasses a cis-syn thymine-thymine dimer efficiently... more The yeast RAD30-encoded DNA polymerase (Pol) bypasses a cis-syn thymine-thymine dimer efficiently and accurately. Human DNA polymerase functions similarly in the bypass of this lesion, and mutations in human Pol result in the cancer prone syndrome, the variant form of xeroderma pigmentosum. UV light, however, also elicits the formation of cis-syn cyclobutane dimers and (6-4) photoproducts at 5-CC-3 and 5-TC-3 sites, and in both yeast and human DNA, UV-induced mutations occur primarily by 3 C to T transitions. Genetic studies presented here reveal a role for yeast Pol in the error-free bypass of cyclobutane dimers and (6-4) photoproducts formed at CC and TC sites. Thus, by preventing UV mutagenesis at a wide spectrum of dipyrimidine sites, Pol plays a pivotal role in minimizing the incidence of sunlight-induced skin cancers in humans.

Journal of Geotechnical and Geoenvironmental Engineering, 1999

Low plasticity silts and silty clays occur extensively in the Central United States, India and Ch... more Low plasticity silts and silty clays occur extensively in the Central United States, India and China. For evaluating their liquefaction potential during an earthquake, no accepted guidelines are available based on their density, void ratio, plasticity index, standard penetration values, or any other simple soil property. Their liquefaction behavior is not properly understood at present and is often confused with that of sand-silt mixtures.

Journal of Geotechnical Engineering, Feb 1, 1996

... Shamsher Prakash Fellow, ASCE, Sanjeev Kumar. Abstract. ... An example problem is included to... more ... Shamsher Prakash Fellow, ASCE, Sanjeev Kumar. Abstract. ... An example problem is included to demonstrate its use. Based on this method, the computed load deflections have been compared with the observed ones and with those based on p-y analysis. ...

Journal of Geotechnical Engineering, 1989

The behavior of piles in seismic areas is significantly affected if the soil liquefies. The stren... more The behavior of piles in seismic areas is significantly affected if the soil liquefies. The strength of the soil and its stiffness decrease due to the increase in pore water pressure. The observed pile damage during earthquakes has provided an insight into the mechanism of soil-pile interaction in liquefying soils. The piles in liquefied soil may undergo large lateral displacements and my fail due to bending or buckling. The paper discusses the observed performance of piles in liquefying soils and the suggested methods for their design.

Journal of the Soil Mechanics and Foundations Division, 1971

This paper presents a comparison of observed computed response of a single pile. Full scale dynam... more This paper presents a comparison of observed computed response of a single pile. Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile driven 17m in a soil profile of uniform silty sand. Horizontal deflection of the pile at the mud line was measured by applying predetermined horizontal load increments during the static test. The dynamic load tests were conducted to determine the amplitude frequency response of the pile subjected to vertical and horizontal vibrations. The natural frequency of free vibrations in the horizontal direction was also measured. The soil properties were determined by conducting in-situ and laboratory tests. The response of the single piles was calculated and compared with the observed response.

The shallow foundations may be subjected to dynamic loads by machine operation or by seismic load... more The shallow foundations may be subjected to dynamic loads by machine operation or by seismic loading. A comparison of observed and predicted response is presented for the case of machine foundations based on observed data obtained by conducting vibration tests on two concrete blocks. For case of shallow foundations for seismic loaoding the recent developments in determining bearing capacity and settlements are discussed and the need for research for developing rational design procedures in this area is highlighted. 1INTRODUCTION The shallow foundations in the form rigid conctrete blocks are commonly used to support reciprocating type machine foundations. These foundations are also commonly used for supporting structural loads which may be static loads or a combination of static and seismic loads. When any foundation is used to support combination of staic as well dynamic loads , it must satisfy the stability criteria for both static as well dynamic loads.

Nature genetics, 2000

Oxidative damage to DNA has been proposed to have a role in cancer and ageing. Oxygen-free radica... more Oxidative damage to DNA has been proposed to have a role in cancer and ageing. Oxygen-free radicals formed during normal aerobic cellular metabolism attack bases in DNA, and 7, 8-dihydro-8-oxoguanine (8-oxoG) is one of the adducts formed. Eukaryotic replicative DNA polymerases replicate DNA containing 8-oxoG by inserting an adenine opposite the lesion; consequently, 8-oxoG is highly mutagenic and causes G:C to T:A transversions. Genetic studies in yeast have indicated a role for mismatch repair in minimizing the incidence of these mutations. In Saccharomyces cerevisiae, deletion of OGG1, encoding a DNA glycosylase that functions in the removal of 8-oxoG when paired with C, causes an increase in the rate of G:C to T:A transversions. The ogg1Delta msh2Delta double mutant displays a higher rate of CAN1S to can1r forward mutations than the ogg1Delta or msh2Delta single mutants, and this enhanced mutagenesis is primarily due to G:C to T:A transversions. The gene RAD30 of S. cerevisiae en...

Contemporary Topics in In Situ Testing, Analysis, and Reliability of Foundations, 2009

Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile t... more Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile that was driven 17m in a soil profile of uniform silty sand and the amplitude frequency response of the pile subjected to vertical and horizontal vibrations was observed. The natural frequency of free vibrations in the horizontal direction was also measured. The soil properties were determined by conducting in-situ and laboratory tests. A comparison of observed and predicted pile response is presented . A comparison of the computed and observed pile response based on the data reported in literature is also presented briefly.

Shallow foundations may experience a reduction in bearing capacity and increase in settlement and... more Shallow foundations may experience a reduction in bearing capacity and increase in settlement and tilt due to seismic loading. The reduction in bearing capacity depends on the nature and type of soil and ground acceleration parameters in non-liquefiable soils. In liquefying soils, the buildings on shallow footings may settle and tilt excessively. The soil- pile behavior under earthquake loading is generally non-linear, which is accounted for by defining soil- pile stiffness in terms of strain dependent soil modulus. Several behavioral and design aspects of shallow foundations and piles subjected to earthquakes have been critically reviewed, both in non-liquefiable and liquefiable soils.

Dynamic Response and Soil Properties, 2007

Geotechnical Earthquake Engineering and Soil Dynamics IV, 2008

Earth Retention Conference 3, 2010

Art of Foundation Engineering Practice, 2010

Design of foundations in earthquake prone areas needs special considerations. Shallow foundations... more Design of foundations in earthquake prone areas needs special considerations. Shallow foundations may experience a reduction in bearing capacity and increase in settlement and tilt due to seismic loading. The reduction in bearing capacity depends on the nature and type of soil and ground acceleration parameters. In the case of piles, the soil-pile behavior under earthquake loading is generally non-linear. The nonlinearity must be accounted for by defining soil-pile stiffness in terms of strain dependent soil modulus. A comparison of observed and predicted pile behavior under dynamic loads has attracted the attention of several investigators. The lateral dynamic pile response of single piles predicted by analytical models often yields higher natural frequencies and lower resonant amplitudes compared to those determined from field tests in horizontal vibrations only. This has been found to be due to overestimated shear modulus and radiation damping of the soil. The authors made an investigation to determine a simple method to improve the theoretical predictions of piles embedded in fine soils. Based upon this investigation shear strain dependent reduction factors are proposed for determining the shear modulus and damping for pile response calculations.

SOILS AND FOUNDATIONS, 1980

抄録 The paper discusses the geotechnical investigations planned and carried out for a cement facto... more 抄録 The paper discusses the geotechnical investigations planned and carried out for a cement factory in boulder deposit. A cement factory normally has very typical structures, eg heavily loaded structures as cement silo, tall structures as preheater tower. In addition to ...

The behavior of piles in seismic areas is significantly affected if the soil liquefies. The stren... more The behavior of piles in seismic areas is significantly affected if the soil liquefies. The strength of the soil and its stiffness decrease due to the increase in pore water pressure. The observed pile damage during earthquakes has provided an insight into the mechanism of soil-pile interaction in liquefying soils. The piles in liquefied soil may undergo large lateral displacements and my fail due to bending or buckling. The paper discusses the observed performance of piles in liquefying soils and the suggested methods for their design.

Molecular and Cellular Biology, 2001

Mutations in the human CSB gene cause Cockayne syndrome (CS). In addition to increased photosensi... more Mutations in the human CSB gene cause Cockayne syndrome (CS). In addition to increased photosensitivity, CS patients suffer from severe developmental abnormalities, including growth retardation and mental retardation. Whereas a deficiency in the preferential repair of UV lesions from the transcribed strand accounts for the increased photosensitivity of CS patients, the reason for developmental defects in these individuals has remained unclear. Here we provide in vivo evidence for a role of RAD26, the counterpart of the CSB gene in Saccharomyces cerevisiae, in transcription elongation by RNA polymerase II, and in addition we show that under conditions requiring rapid synthesis of new mRNAs, growth is considerably reduced in cells lacking RAD26. These findings implicate a role for CSB in transcription elongation, and they strongly suggest that impaired transcription elongation is the underlying cause of the developmental problems in CS patients.

Molecular and Cellular Biology, 2001

The yeast RAD30-encoded DNA polymerase (Pol) bypasses a cis-syn thymine-thymine dimer efficiently... more The yeast RAD30-encoded DNA polymerase (Pol) bypasses a cis-syn thymine-thymine dimer efficiently and accurately. Human DNA polymerase functions similarly in the bypass of this lesion, and mutations in human Pol result in the cancer prone syndrome, the variant form of xeroderma pigmentosum. UV light, however, also elicits the formation of cis-syn cyclobutane dimers and (6-4) photoproducts at 5-CC-3 and 5-TC-3 sites, and in both yeast and human DNA, UV-induced mutations occur primarily by 3 C to T transitions. Genetic studies presented here reveal a role for yeast Pol in the error-free bypass of cyclobutane dimers and (6-4) photoproducts formed at CC and TC sites. Thus, by preventing UV mutagenesis at a wide spectrum of dipyrimidine sites, Pol plays a pivotal role in minimizing the incidence of sunlight-induced skin cancers in humans.

Journal of Geotechnical and Geoenvironmental Engineering, 1999

Low plasticity silts and silty clays occur extensively in the Central United States, India and Ch... more Low plasticity silts and silty clays occur extensively in the Central United States, India and China. For evaluating their liquefaction potential during an earthquake, no accepted guidelines are available based on their density, void ratio, plasticity index, standard penetration values, or any other simple soil property. Their liquefaction behavior is not properly understood at present and is often confused with that of sand-silt mixtures.